Weighted Random Early Detection (WRED) is a queuing discipline for a network scheduler. It is used to avoid traffic congestion. WRED is an extension to Random Early Detection (RED) in which a single queue may have several different sets of queue thresholds. Each traffic class has a different queue threshold (soft threshold and hard threshold).

WRED uses multiple input queues that are prioritized by the protocol of the packet. If there is enough processing capacity to empty all the queues then it processes all incoming packets. If the incoming packet rate is higher than the processing capacity, lower priority traffic may be dropped. NIOS has a fixed amount of memory for networking buffers in any system; WRED makes sure there is enough memory for the system to operate even under extreme traffic load.

Low priority traffic can be of the following types: TCP, UDP, ICMP, and other non- TCP, UDP, and ICMP protocols that are non-control plane protocols. Use set wred command to enable or disable WRED feature and to get threshold limit for different queues.  To check the WRED status see show wred

Syntax

set wred [ enable| disable ] [Thresholds T1/T2/T3 ]

Example

Infoblox > set wred enable

For port 0: eth0

rx wred filter is enabled: rxd_thres1=256, rxd_thres2=384, rxd_thres3=427, rxd_count=512

Infoblox >set wred disable

For port 0: eth0

rx wred filter is disabled: rxd_count=512

Infoblox >set wred 384 427 470

For port 0: eth0

rx wred filter is enabled: rxd_thres1=384, rxd_thres2=427, rxd_thres3=470, rxd_count=512